Infrared diagnostics of stellar evolution in nearby galaxies

Suresh Sivanandam (David Dunlap Observatory)

The infrared window offers a unique opportunity to study galaxy evolution in the nearby
Universe. I will discuss our Spitzer/Herschel study on how the intracluster medium (ICM)
impacts the evolution of galaxies in nearby clusters. We discovered direct evidence that the
ram-pressure from the ICM is stripping the molecular component of galaxies, immediately
affecting the evolution of infalling cluster galaxies. This challenges the traditional view
that ram-pressure can only strip the least dense, atomic gas. I will also discuss an upcoming
survey I am leading to characterize the stellar populations of nearby galaxies in the
near-infrared. This program will be carried out using a novel wide integral field infrared
spectrograph (WIFIS) that we are commissioning later this year. Due to the growing evidence
for the variation of initial mass function (IMF) slope in nearby galaxies, characterizing the
IMF in these systems will be the main focus of our survey. The abundance of dwarf and giant
sensitive spectral features, only visible in the near-infrared, will greatly improve the
measurements of the IMF slope. Finally, I'll end with future prospects for the study galaxy
evolution at higher redshift using an innovative AO-fed, near-infrared multi-object
spectrograph we are currently designing.